Heat recuperator structure in a rotary cement kiln



July 28, 1970 R. BUCCHI. 1,8

HEAT RECUPERATOR STRUCTURE IN A ROTARY CEMENT K'ILN" Filed Aug. 13, 1968 INVENT OR iEA/A 7-0 506097 United States Patent 3,521,867 HEAT RECUPERATOR STRUCTURE IN A ROTARY CEMENT KILN Renato Bucchi, Bergamo, Italy, assignor to S.p.A.

Italcementi Fabbriche Riunite Cemento, Bergamo, Italy, a company of Italy Filed Aug. 13, 1968, Ser. No. 752,336 Claims priority, application Italy, Aug. 18, 1967, 19,599/ 67 Int. Cl. F27b 7/00 US. Cl. 263-33 3 Claims ABSTRACT OF THE DISCLOSURE Heat recuperator structure in rotating kilns for manufacturing cement wherein are provided means for compensating the thermal expansion of the walls thereof.

Rotating cement kilns furnished with heat recuperators are well known in which the initial part of the kiln is subdivided into a number of sectors by means of dividing walls arranged in radial planes, connected one to the other along the axis of the kiln and supported at their periphery by the shell of the kiln itself. The drawbacks that result from the deformation of the said dividing walls as a consequence of the elastic deformation of the shell and thermal expansion are also well known.

The object of this invention is a heat recuperator structure in a rotating cement kiln which eliminates these drawbacks by basing itself on the concept of eliminating the central rigid connection, at the same time ensuring a seal sufiicient to impede any appreciable passage of material during the rotation of the kiln from one sector to the other.

The structure is in fact characterized by the fact that the dividing walls are fixed only at their outside edge in a cantilever manner to the shell of the kiln and they terminate towards the center in curved or channel-like inclined elements of which each one partially covers the next without touching it to thereby form a tortuous passage, and which permits expansion and impedes the passage of material from one sector to the other.

In practice each wall is formed from equal adjacent wall elements, each of which is furnished with its curved element.

Naturally the clearance between the various curved elements is determined as a function of the radial length of the dividing wall, of the working temperature and of the possible elastic deformation of the shell of the kiln.

For greater clarity one embodiment of the invention has been illustrated in the accompanying drawing in which:

FIG. 1 shows the schematic section of a rotating kiln at the recuperator;

FIG. 2 shows a perspective view of a dividing wall element;

FIG. 3 shows a part of the section shown in FIG. 1 but on a larger scale.

In the drawing the shell of the kiln is indicated by 1 and its refractory lining by 2, while the dividing walls "Ice which form the heat recuperator when assembled in radial planes are indicated by D.

Each wall D is formed in effect from a number of wall elements such as 3 (FIG. 2) furnished with ribs 4 and with a shaped base 5 with holes 6 for its fixing to shell 1 by the interpositioning of a seat 7.

At the opposite extremity to that indicated by 5, the wall element 3 is provided with further holes for its fixing by means of bolts 8 to a curved element 9 which has a profile in the transversal section such that it partially covers the curved element of the preceding wall and itself is partially covered by the curved element of the Wall after it, the clearance between the curved elements of the various walls being predetermined on the basis of the various calculated expansions of the walls and elastic deformations of the shell such that the curved elements do not come into contact with each other and that they limit to a minimum the passage of material from one compartment to the other.

What is claimed is:

1. Heat recuperator structure in a rotating lime kiln which includes a number of walls arranged in radial planes on the inside of the initial section of the kiln such that it subdivides it into a number of sectors which are open at the two ends, in which the said dividing walls are assembled in a cantilever manner by fixing them only to the shell along that side of them which is parallel to the axis and furthest from it, the other parallel side which is nearest to the axis being left free from any form of reciprocal rigid connection, each of said walls being provided along its free side close to the axis of the kiln with a channel-like element having a base portion and two generally upstanding side portions.

2. Structure as claimed in claim 1 wherein said base portion of each of said channel-like elements is inclined to the radial plane of its corresponding wall and partially overlaps, without touching, a portion of the next adjacent channel-like element on its one side and which itself is partially overlapped by the next adjacent channel-like element on its other side, the spacing between the overlapped portions of said elements being predetermined so as to ensure the free expansion of each separate wall.

3. Structure as claimed in claim 2 wherein the overlapping and overlapped portions of each of said channellike elements include its generally upstanding side portions, and tortuous passage means formed between said overlapping and overlapped portions of adjacent ones of said channel-like elements for impeding the passage of material from one of said sectors to others of said sectors.

References Cited UNITED STATES PATENTS 1,920,677 8/1933 Burke 263-33 2,020,960 11/1935 Pehrson et al 263-33 X 3,036,822 5/1962 Andersen 263-32 JOHN J. CAMBY, Primary Examiner US. Cl. X.R. -89 

